Tips for getting the best Prime Day deals

SAN FRANCISCO — The off-season sale Amazon calls Prime Day hits July 12. If you're thinking of taking part, you'll save money and time by planning ahead.

Here's how to prepare yourself ahead of the marketing bonanza, from apps that alert on price drops to asking Alexa.

Decide whether it's worth joining Prime

Amazon says it will offer more than 100,000 deals over the course of the day, more than twice the number offered last year. Most will be the items lowest price ever or within the last year, according to the Seattle online retailer.

The catch: the deals are only available to members of Amazon Prime, the $99-a-year membership program that offers free two-day (and sometimes one- and same-day) shipping as well other perks, including streaming video, music and photo storage. You can see a full list here.

Although Amazon CEO Jeff Bezos said in his annual letter to shareholders this year that he wants to make Prime such a good value it would be "irresponsible not to be a member," it's certainly not for everyone. If you're not already a Prime member, you first need to decide whether you'd save enough to make up for buying a membership.

That said, it's also possible to sign up for a free 30-day trial, then cancel after Prime Day. Amazon's betting you'll be so blown away you'll stick around.

This year Amazon's Prime Day is July 12

Make a list

The whole idea here is to save money, so while shopping for the sake of shopping might shore up the U.S. economy as a whole, it won't do much for your own bottom line. Spend some time thinking of bigger-ticket items you need over the next six months or so.

If you have adequate storage space, holiday shopping can also figure into that. (Think what a feeling of smug calmness you'll have if all your Christmas shopping is done in July.) Also include household items you know you'll need more of. Last year's Prime Day included things like vitamins and snow shovels.

Check it. Twice.

Write the list on a piece of paper, a word processing document or a spread sheet. Go online and tool around a little, checking to see what brand, make and model of those items you want. Read some reviews, get a sense for what's out there. Once you've narrowed down your range, add them to your list.

Now hit a couple of likely sites and get some ballpark prices for those items. You can also search by the item's specific name on Google, Bing or Yahoo and see a fairly wide range of options. Write down the prices and which site it came from on your list.

It's helpful to go back a second day and re-run at least the bigger ticket items, as sometimes prices can vary a lot day-to-day.

Armed with your master shopping list with prices, you'll be in a strong position to evaluate deals as they are launched.

Don't get excited about Amazon Prime Day yet

Check out Amazon rivals

While Amazon has already begun running a few pre-Prime Day deals, the real blizzard will be the 24 hours beginning at midnight on July 12, Seattle time.

But Amazon's not the only company offering sales this week. A host of others are jumping on the bandwagon. So it's worth looking around on some of the bigger retailers, especially Walmart, Best Buy, Target and Macy's to see if they've got any deals going.

App it

A must-have for this exercise is the Amazon app on your phone, which allows you to set a watch list of products. It will notify you just before they go on sale. To sign up, tap “notifications” (this may be in Settings) in the app menu and enable Your Watched & Waitlisted Deals.

You can also add items to your Amazon shopping list or wish list. Amazon will alert you if any of the items in your list are available at a lower price.

There are also other apps you might want to get, or bookmark. A popular one is CamelCamelCamel, which allows you to look at an item's price history on Amazon. So when a deal pops up during Prime Day, you can see if whether it really is a deal. You can also set it to alert you when the price of an item you're interested in on Amazon falls below a certain point you set.

Ask Alexa

Owners of an Amazon Alexa device, such as the Echo, Dot or Tap, can also ask the digital assistant if she knows of any Prime Day deals.

Amazon customers who order by voice will have access to exclusive deals during the online retailer's Prime Day sale.

Alexa users will receive a  $10 discount on their first Amazon order using Amazon Echo, Echo Dot, or Amazon Tap, July 8 through July 12.

Alexa's Prime Day deals revealed

Find a shopping buddy

Let's hope that you don't plan to spend the entire 24 hour period of the sale online, relentlessly hitting the refresh button on the Amazon screen so you don't miss any deals. Really. Life's too short and sleep's too important.

But a nice way to socialize the whole online shopping experience is to get a shopping buddy or three. Find a group of people, distribute your lists amongst yourselves and then have everyone sign up for shifts. That way you don't have to skip that important meeting at work or a hot date just to make sure you aren't missing the all-important hedge trimmer your backyard so desperately needs.

Finally, think before you buy

But most importantly, remember that the entire point of a sale is to save money. You haven't saved money if you bought something you don't need and soon won't want. So be cautious of getting caught up in the frenzy that Amazon, and others, are working so very hard to create. If you buy a set of wireless headphones that cost $120 but are $40 off, you've still spent $120. So if you didn't really need them, you haven't saved $40 — you've wasted $120.

Follow San Francisco-based tech reporter Elizabeth Weise @eweise.